The four couples who have filed suit against the state of Tennessee over its constitutional ban on same-sex marriage. Left to right: Dr. Valeria Tanco and Dr. Sophy Jesty; Johno Espejo and Matthew Mansell; Kellie Miller and Vanessa DeVillez. Not pictured: Ijpe DeKoe and Thom Kostura.

"The couples in the lawsuit have been welcomed to Tennessee by their neighbors, employers and communities. But the law still treats them unequally and denies them the ability to take care of one another and their families."

In November 2006 Tennessee voters considered Amendment 1, a ballot proposal that defined marriage as being only a contract between one man and one woman.

Tennesseans overwhelmingly passed the measure, with Amendment 1 garnering 81 percent of the vote. Tennessee had been one of seven states to pass such measures via referendum in 2006.

The NCLR lawsuit on behalf of the four couples is not the first legal trouble that Amendment 1 has weathered.

In 2005 the state chapter of the American Civil Liberties Union attempted to remove proposed amendment from the ballot.

Sharon Curtis-Flair, director of communications for the Tennessee Attorney General's Office, told The Christian Post that as of Tuesday afternoon the state has not been officially served the lawsuit. As a result, no official statement could be made on the matter by press time.

"Meanwhile, we did receive a 'courtesy copy' which means we have not yet been officially served," said Curtis-Flair, adding that last summer's Supreme Court decision on DOMA has not affected the state laws.